From: Joel VanderWerf <vjoel@...>
Date: 2006-03-21T15:04:14+09:00
Subject: Re: rake rules with multiple prerequisites

Joel VanderWerf wrote:
> Joel VanderWerf wrote:
>> Jim Weirich wrote:
>>> The problem is that a plain string in the *rule* dependency list already 
>>> has a meaning: it is the file extension to be used in the name of the 
>>> source file for the target.
>> That's what I was guessing. I'll stick with procs, as you suggest below:
>>
>>> You can do this:
>>>
>>> generic_files = FileList["foo", "bar", "baz"].collect { |fn| lambda { fn 
>>> } }
>> Thanks!
>>
> 
> On second thought... would it be possible for the proc to *return* a
> FileList? It doesn't seem to work now, but it would be a nice feature,
> wouldn't it?
> 
> $ cat rakefile
> generic_files = proc {FileList["foo", "bar", "baz"]}
> 
> rule /^site_\w+/ => [
>   proc {|fn| "__#{fn}"},
>   generic_files
> ] do |t|
>   p t.name
> end
> 
> task :__site_stuff
> 
> file "foo" do touch "foo"; end
> file "bar" do touch "bar"; end
> file "baz" do touch "baz"; end
> 
> $ rake site_stuff
> (in /home/vjoel/ruby/misc/rake)
> rake aborted!
> can't convert Rake::FileList into String
> 
> (See full trace by running task with --trace)
> $
> 

I found a small patch to make this example work, but of course it could
break something else. It seems like a natural thing to do: just flatten
the result of Rake::TaskManager#make_sources. Normally, the result would
be an array of strings, but this patch allows the translation procs to
return an array of filenames (or a FileList), rather than just one.

--- rake.rb.bck 2006-03-20 22:00:12.000000000 -0800
+++ rake.rb     2006-03-20 22:00:12.000000000 -0800
@@ -1427,7 +1427,7 @@
        else
          fail "Don't know how to handle rule dependent: #{ext.inspect}"
        end
-      }
+      }.flatten
     end

   end




-- 
      vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407